System of electrical distribution



March 10, 1931. i g wCoDBRlDGE 1,795,462

SYSTEM OF ELECTRICAL DISTRIBUTION Filed March 1,, 1925 //VI EIVTO/P W/T/YESS. W .cy 66 r r6 44 vase/m Z w y Patented Mar. 10, 193i 1,795,462

UNITED STATES PATENT; OFFICE JOSEPH LISTER WOODIBBIDGE, OI PHILADELPHI A, PENNSYLVANIA BYS'IEI OF ELECTRICAL DISTRIBUTION Application filed larch 1, 1928. Serial 10. 91,362.

This invention relates to systems in which direction when the battery is charging. On

a storage battery is arranged to be charged this ampere hour meter are provided two from a suitable source of current and to be stationary contacts 17 and 18 located ,in

discharged into aload circuit to which transthe path of the arm 16 in such positions 6 lating devices are connected, and is especialthat when the ampere hour meter indicates l ly applicable to cases where-the load on the that the battery is fully charged the arm 16 load circuit is variable or intermittent in charwill be in-c'ontact with the contact point 17 acter making it desirable to vary the amount and when the battery is discharged by a of charge put into the battery from time-to certain predetermined amount, the arm 16 10 time to restore what has been taken ut. One will have travelled until it is in contact with 60 of the objects of my invention is to make the the contact point 18. The arm 16 is connectcharging of the storage battery entirely autoed to the conductor 2 by means of conductor matic and at the same time to provide for the 21. Contact 17 is connected by conductor necessary amount of overcharge to compento one terminal of the tripping coil 11 'of sate for the losses in the battery. My inventhe circuit breaker 9, the other terminal of 6 tion. is especially eifective in providing for a this coil being connected through the auxmore accurate adjustment of the charging lhary contacts 12 to conductor 1. Contact current than has heretofore been possible 18 of the ampere hour meter is connected by with known automatic means of this general conductor 19 to one terminal of the closing kind and accomplishes this with comparacoil 10 of the circuit breaker 9, the other 7 tively simple, reliable and inexpensive apparm n l Of this. coil being connected ratus. through auxiliary contacts '13 to conduc- My invention will be more readily undertor 1. Thus when the arm 16 of the stood by reference to the following descripampere hour meter makes contact with contion of one embodimentthereof, taken in cont ct poipt 17, the circuit through the tripnection with the accompanying drawings in ping C011 11 of the circuit breaker will be which completed, provided the auxiliary contacts Figure 1 represents diagrammatically a 12 are bridged by the contact piece 22, which system of electrical distribution embodying willbe the case when the circuit breaker 9 the invention; and is closed. This will trip the circuit breaker Figure 2 similarly shows amodification. and open the circuit of the charging resist- In Figure 1, 14 is a storage battery con ance 7. At the same time the contact piece nected to'ithe load circuit 3, 4, to which are 22 Will be moved by the opening of the circonnected the translating devices 5 thr u h cuit breaker out of contact with the auxsuitable switches 6. 1, 2 repre nt the ciriliary contact points 12 and into contact with cuit of anysuitable charging source for the the auxiliary Contact points 13, thus constorage battery, the conductor 2 being dinecting the closing coil 10 of the circuit rectly connected to one terminal of the batbreaker to conductor 1. If now the battery tery, while the conductor 1 is connected to discharges into the load circuitcausing the the opposite terminal of the battery through arm 16 of the ampere hour meter to travel in a resistor 8 and also through another resisthe direction of the arrow until it makes contor 7. Included in the circuit of the latter tact with contact point 18, the closing coil resistor a circuit breaker 9 arranged to 10 will be energized and the circuit breaker automatically connect and disconnect the re- 9 will close thus reconnecting charging re- .sistor 7 as will be hereinafter described. Besistance 7. 4

tween the battery 14 and the conductor 3 of It will be noted that. current from the batthe load circuit is an ampere hour meter 15 tery to the load circuit. asses through the provided with a moving arm 16, which travampere hour meter in t e discharge direcels in thedirection of the arrow when the tion, while current from conductor' '1 battery is discharging and in the opposite through resistor 7 passes tothe battery-1 through the ampere hour meter in the charge direction, whereas current from conductor 1 through resistor 8 passes directly to the battery without pass ng through the ampere hour meter. When there is no demand on the load circuit, this currentpasses through the battery in the charge direction without affecting the ampere hour meter. YVhen there is a demand on the load circuit, this current through resistor 8 supplies a part of the-demand, thus reducing the hattery discharge but the current in the ampere hour meter is still unafiected by this current through the resistor 8, the net result in respect to the total amount of overcharge given to the battery being the same. The ampere hour meter should be designed to run more slowly in the charge direction than in :the discharge direction, thus providing for a certain percentage of overcharge to compensate for the ampere hour efliciency of the battery. The ampere h'our meter described above, as well as the circuit breaker, are well known pieces of apparatus, and can readily be obtained on the market, so that it is not necessary to enter into a more detailed description of these devices;

The combination of the battery and.ampere hour meter and circuit breaker and resistor 7 and their circuit connections is well known in the art, and has been extensively I used for the automatic control of storage battery charging. It provides for giving the battery a certain percentage of overcharge,

that is, the number at ampere hours put into the battery during the'charge is a certain percentage in excess of the number of ampere hours taken out duringv the previous dis- 7 charge. Wherethe battery is operated run der conditionscalling' for daily discharges amounting to a very considerable proportion .ofits capacity, this method of'operation is quite satisfactory, since the principal losses to be provided for by battery overcharge are those due to the inefficiency of the charging current, some of which is necessarily wasted n gassing toward the end of charge and the amount of this loss is roughly proportionate to the amount of charge. If, however, the

battery is subjected to only occasional dis-v charges of small amount or at comparatively long intervals of time, the standing losses in the battery, due to local action, may become a very considerable proportion of the total losses or may constitute the principal amount of the losses to be compensated for. These .standing losses bear no -proportion to the amount of discharge, but are approximately proportional to the total elapsed time and they cannot, therefore, be accurately provided for by the adjustment of the ampere hour meter to run a certain percentage slower on charge than on discharge. To provide for these standing losses I have shown the resistor 8 connected between conductor 1 and. the

corresponding terminal of the battery, the point of connection to the battery circuit being located between the battery and the ampere hour meter, so that the charging current passing throllgh resistor 8 does not pass through the ampere hour meter. It will further be noted that the current passing through resistor 8 is flowing continuously and is not interrupted by the circuit breaker 9. r

In Figure 2 a modification is shown in which the charging current through resistor 8 passes through the ampere hour meter as well as the current through resistor 7. However, the circuit of resistor 8 is not interrupted. by the circuit breaker 9, and therefore transmits charging current continuously suitable for compensating for the internal losses in the battery. The eflect of this current on the ampere hour meter will usually be negligible since this instrument is usually designed so that when the hand reaches the stop 17. indicating a fully charged condition of the battery, it will not travel further in the charge direction even though the charging current continues to flow. I

It will he noted from the above that I am providing two paths for charging current into the storage battery, one of which is continuously closed and transmits current suitable for compensating for the standing losses in the battery, and the other is opened and closed automatically by a device responsive tothe currentin the external battery circuit.

It will be, obvious to those skilled in the artthat modifications may be made in details of construction and arrangement without'depart-ing from the spirit of the invention which is not limited as to such matters or otherwise than as the prior art and the appended claims may require.

' I claim:

1. In combination a storage battery and its load circuit, an ampere hour meter con-' nected between the battery and the load circuit and having a traveling arm and spaced contacts in the path of the travel of the arm, a charging source, a charging circuit adapted to transmit current from the source to the battery through the ampere hour meter, said circuitincluding a circuit breaker" having opening and closing coils connected respectivelyto said spaced contacts to open the circuit breaker at full charge and to the internal losses of the battery, another circuit for transmitting charging current to the battery, means responsive to the state of charge of the battery for opening and closing the last named circuit without afiecting the first, and aload circuit connected to the battery.

5 3. In combination, a storage battery, a charging source, a load circuit connected to the battery, a circuit for transmitting continuously from the source to the battery a charging current ada ted to compensate for the internal losses 0 the battery, a second charging circuit for transmitting to the battery a charging current adapted to com nsate for the losses due to the load on the attery, and means responsive to the state of charge of the battery for opening and closing the second chargin circuit without affecting either of the ot er circuits.

4. In combination, a storage battery, a charging source; a circuit for transmitting continuously from the source to the battery a charging current adapted to compensate for the internal losses of the battery; a second charging circuit for transmitting to the battery a charging current adapted to compensate for the losses due to the load on the battery; said second charging circuit containing a. circuit breaker and an ampere hour meter; means controlled by said ampere hour meter for opening and closing said circuit breaker; and a load circuit connected to the battery between the battery and the circuit breaker.

5. In combination a storage battery and its load circuit, an ampere hour meter connected between the battery and the load circuit and having a traveling arm and spaced contacts in the path of the travel of the arm, a charging source, a charging circuit adapted to transmit current from the source to the battery through the ampere hour meter, said circuit including a. circuit breaker having opening and closin coils connected respectively to said spacer? contacts to open the circuit breaker at full charge and to close it when the battery is discharged to a predetermined amount and a second charging circuit permanently connecting said battery with said char ing source.

0 JOSE H LESTER WOODBRIDGE. 5 

